Adsorption Isotherms Complexation of Some Amino Acids with Co(II) Ion on Carbon Nanotube

Abstract

In this research investigatiof the adsorption isotherms and the effect of solution conditions such as pH and concentration of complexation of some amino acids with cobalt(II) nitrate six-hydrate upon multi-wall type carbon nanotube (CNT). The adsorption capacity of complexation of amino acids onto the surface of carbon nanotube increased with the pH from acidic to alkaline. At pH = 9 the affinity order of the complexation of amino acids towards carbon nanotube is L-arginine > L-phenylalanine > L-asparagine > L-methionine > L-cysteine > glycine > L-alanine > Lvaline > L-histidine. The curves have an important role in the design and optimization of the unit operations such as preservation, drying storing packaging and mixing. The adsorption equilibrium isotherms were fitted by Freundlich, Langmuir and Temkin models, but the Freundlich model is better than other models because is does not assume the surface as homogeneous with respect to adsorption energies and also the r2 value indicates the goodness of fit between the data and the isotherm.